Australia leading the world in Salmonella outbreaks

Did you know that Australia currently has more Salmonella outbreaks than any other country? 73 cases per 100,000 people, or just over 17,000 cases were recorded in 2015, according to the CSIRO, which has taken a closer look at the troublesome bacteria in the wake of the recent contamination of leafy greens.

Salmonella is the second highest cause of bacterial foodborne gastroenteritis in Australia, after Campylobacter. Along with Listeria monocytogenes, Salmonella is responsible for more deaths in Australia than any other foodborne disease, each accounting for about 15 deaths per year.

It’s difficult to tell whether foodborne illnesses overall are on the rise or not, but certainly detection, tracing and reporting systems have all improved, and social media enables more people to hear about outbreaks easily and quickly.

CSIRO believes the recent outbreak was unusual, however, because it was in leafy greens, it was nationwide and the serotype was Salmonella anatum, which can cause disease in humans, but in Australia is most frequently isolated from animals such as cattle, sheep, pigs, goats and chickens, and their environments. It has also been found in foods such as nuts, meat, imported herbs and spices, along with animal feeds and in dairy factory environments.

There are over 2000 different serotypes of Salmonella and Salmonella anatum is relatively uncommon in humans. Symptoms are similar to infection caused by other Salmonella — fever, diarrhoea, vomiting and abdominal discomfort — but it appears to be a milder and shorter lived form.

While Salmonellosis has been linked to consumption of horticultural produce internationally — in the US alone seed sprouts and tomatoes are frequently identified as vehicles for salmonellosis — Salmonella anatum was suspected in only one or two out of dozens of outbreaks.

On social media many consumers stated they were safe from the recent outbreak, because they always wash prepackaged greens before consumption. The reality is, this practice may reduce, but will not eliminate, bacteria like Salmonella. And bagged salad products are washed, sanitised and rinsed several times during processing to slow unwanted bacterial growth. Temperature controls from farm to supermarket are also designed to keep refrigerated food products safe to eat.

More research is needed in finding out how Salmonella is transmitted and what can be done about it. In the meantime, the best way to reduce the risk of foodborne illness is to ensure hands are washed, food is stored correctly (salad bags should be kept at 5° or colder), food is cooked properly and raw and cooked foods are separated during storage and preparation.